Sparking plug for internal-combustion engines



G. B. SYKES Filed June 14, 1921 2 Sheets-Sheet. l

SPARKING PLUG FOR INTERNAL COMBUSTION ENGINES Jlyg 8, 1924.-

v A 1,500,161 G. B. sYKEs SPARKING PLUG FOR INTERNAL COMBUSTION ENGINES 2 Shea ts-Shet 2 Filed June 14, 1921 Patented July 8, 1924.

UNITED STATES GERALD BASIL SYKES, OF CLECKHEATON, ENGLAIN'D.

SPARKING PLUG FOR INTERNAL-COMBUSTION ENGINES.

Application led June 14, 1921.

To all who/m, t may concern:

Be it known that I, GERALD BAsiL SYKES, residing at St. Johns House, St. Johns Place, Cleckheaton, England, have invented new and useful Improvements in or Relating to Sparking Plugs for Internal-Combustion Engines, of which the following is a specification.

This invention has reference to sparking plugs of the type or kind in which earth or negative electrode or electrodes is or are in strip form and is or are inserted in a groove or grooves formed in the periphery of the insulating body of the plug and clamped either directly between a circular projecting portion of the insulating body and a lat annular seating in the body of the plug or by a. ring placed upon the seating and clamped in position by the said projection and a cap nut.

With the above named arrangements there is a danger of the earth or negative electrode or electrodes becoming detached from the insulating body and its or their supporting ring and falling into the cylinder.

The object of this invention is to overcome the above difiiculty by first forming the earth or negative electrode or electrodes separately and then securely fixing it or them to the inner periphery of a metal ring at a suitable distance from its upper edge so that the metal ring is capable of being clamped in position between a tapering annular faced seating in the body of the plug and the tapering face of a circular projection formed on a metal sleeve by a cap nut screwed on to the upper end of the body of the plug.

According to this invention the metal ring` to which the earth or negative electrode or electrodes is or are securely Xed is made of any required depth and of such a diameter that it will easily lit on to a metal sleeve and into a recess formed in the u-pper portion of the body of the plug and rests upon a shoulder therein having a tapering face. The ends of the ring are correspondingly tapered t0 lit respectively against-for forming a gas-tight joint,-the tapering face of the circular projecting ring of the metal sleeveand the said seating.

.Provision` is made for either removing the positive electrode, insulating body and wrappings/and the sleeve forming one unit separately or together with the ring and its Serial No. 477,580.

electrode or electrodes forming another unit.v

In the drawings hereunto annexed Fig. l is an outside eleva-tion of the sparking plug;

Fig. 2 a part vertical section of the same;

Fig. 3 a part sectional elevation of the central positive electrode, metal sleeve and insulating body;

Fig. an elevation of the metal sleeve with vertical groove cut therein;

Fig. 5 a plan of sam-e looking at the top of Fig. 4;

Fig. 6 a plan loo-king at the lower end of Fig. 4;

Fig. 7 a sectional elevation of the retaining ring with the earth or negative electrode in position;

Fig. 8 a plan of the lower end of Fig. 7

Fig. 9 an elevation of the retaining ring;

Fig. 10 a plan looking at the lower end of Fig. 9.

All the views are drawn to an enlarged scale.

a is the usual casing or body of the plug provided with reduced and screw threaded ends b, c, and with the central hole d having a shoulder with a tapering face d1 therein. A cap nut e is mounted upon the upper screw-threaded portion c. The central positive electrode consists of a stem f provided with an enlarged tapering end f1. The upper end of the electrode is provided with the usual terminal screw f2 and nut f3. On the stem of the central electrode f is mounted the insulating body consisting of a sleeve made in two portions g, g1. The insulating portions g, g1 are each formed of a. number of mica washers cornpressed together and afterwards turned to the shape shown in the drawings. A metal sleeve it is also mounted upon the said stem and interposed between the mica portions g, g1. The sleeve h is insulated from the stem f by two' mica wralppings 1 and 2 of different lengths.

On the metal sleeve z. is a circular projection h1, the upper face of which is at or about a right angle to the insulating wrappings l and Q whilst the under face of the projection Ll is tapered at a suitable angle, say, at or about thirty degrees. The insulating body g, g1 is made of several diameters in its length, as shown at Figs. 2 and 3. The stem of the central positive electrode f is made to fit the central hole in the portions of the insulating body` g, g1 and the mica wrappings 1 and 2. he upper portion g of the insulating body rojects above the cap nut e and is tapered) as shown at `Figs. 1 to 3, and on its upper end above the mica portion g there is a brass washer z', a brass nut j, a steel spring washer Z and a lock nut c; the just mentioned nuts being screwed upon the stem f, and they are employed for compressing the whole of the insulating body g, g1 and retaining it in position on the stem f against the enlarged portion f1. The enlarged portion f1 of the central positive electrode is made the same diameter as the lower end of the portion g1 of the insulating body, and the said enlarged portion f1 projects a suitable distance below the reduced screw portion b of the body of the plug. One or more vertical grooves m is or are formed in the peripheries of the sleeve k and upper part of the mica insulating portion g1 for the reception of the earth or negative electrode or electrodes n.

The metal ring o is made of the same diameter as the circular projection h1 of the metal sleeve k and to easily lit into the enlarged portion of the central hole d at the upper part of the body of the plug. The ring o is made of any required depth and its upper edge is about level with the top of the screw-threaded portion c of the body of the plug. The central hole in the ring 0 is made of such a diameter that it will easily fit on to the cylindrical, parallel portion k2 of the sleeve L. The upper and lower edges 01, o2 of the ring o are arranged totaper towards the paralled portion h2 of the sleeve h at or about an angle, say, of thirty degrees so as to lit respectively against the tapering faces of the circular projection h1 and shoulder or seating d1 for forming gas tight joints. In the inner periphery of the ring o is or are formed one or more transverse holes o3 and one or more vertical grooves o4 for the reception of the upper end n1 of the earth or negative electrode fn. The hole or holes o3 are arranged of the ring -f and the outer portion of the said end is riveted or otherwise suitably secured to the ring level with its outer periphery. The main pendant portion of the earth or negative electrode n projects a suitable distance into the central hole of the ring 0 so as to engage with, and easily slide in, the groove m, (Fig. 4), and the lower end of the said electrode is inclined inwards towards the enlargement f1 of the positive electrode at a similar angle.

By `arranging the metal ring 0,*-and negative electrode n attached thereto,-to easily lit into the body of the plug it may be separately and readily removed after the positive electrode, the insulating body and wrappings and the metal sleeve forming the unit have been previously removed, or the whole of the said parts may be readily removed together from the body of the plug for inspection, adjustment, cleaning, renewal and other -purposes without there being any danger of the earth or negative electrode or electrodes n falling into the cylinder when the cap nut e and the positive electrode and parts connected therewith are withdrawn.

What I claim is In a spark plug, the combination of a casing having a central hole and a tapering face therein, a positive electrode eXtendin vthrough said casing, an insulated meta sleeve having an annular projection and a tive electrode within the casing, a vertical -tapered lower surface encircling said posigroove in the periphery of said sleeve, a

negative electrode extending within said groove, and a grooved ring having ta ered ends adapted to engage said sleeve an said negative electrode.

GERALD'BASIL SYKES. Witnesses:

W. FAIRB'UnN-HART, ALICE M. TURNER. 

